The Prince's Resistance
by Blonde Panther
Summary: FE8. Lyon had no idea what he was letting into his mind and body when he split the Fire Emblem. He lives to regret that decision, but for Eirika's sake, he would fight back the parasite's control. Also Fomortiis is totally not on the character list.


**Disclaimer:** Fire Emblem and all related names and concepts belong to Nintendo and Intelligent Systems.  
 **Characters and Pairings:** One-sided Lyon/Eirika, Fomortiis.  
 _ **Author's Notes:** Ruled/Revolt. This is the fic for which I wanted to use Fomortiis, since I didn't want to use the prompts in the governmental/royalty sense. Additionally, Lyon is a wonderful antagonist and I couldn't not do something with him during FE8Week._

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His entire body ached when he woke up, and he needed all his willpower to not scream out in agony, shame, and rage when he realised why that was. He hadn't woken up at all, because he had not been asleep- rather, he had been fully under the control of... that _thing._ The parasite that fed off of his insecurities and drained his sanity, a little more every day. He attempted to straighten and flatten his hair with his hands as he regained control over his limbs and started walking, wondering what the Demon King had used his body for this time. He just hoped it hadn't hurt anyone, least of all Eirika...

He knew it was fascinated by the princess of Renais, much more so than with her twin brother, even now that it could no longer prevent them from claiming their own Sacred Stone for use against it. Lyon knew why. Fomortiis –that was the thing's name, he had learnt during its stay in his mind- wanted to break him. By hurting Eirika, it knew that it could erode Lyon's mind much more quickly than if it just influenced him from inside out. It wanted his body. His magic. Lyon had been, and still was, weak enough that the Demon King had been able to possess him, but his raw power and potential was almost unrivalled in Magvel. That, coupled with the rare and powerful tomes of Dark magic he had access to as prince of Grado, made him a perfect vessel through which to channel its resurrection.

That was something Lyon had to prevent, at all costs. It had been at the cost of their own lives and that of almost every soldier in their company that the hero Grado and his companions had been able to seal it. If it returned now, it would devastate Magvel, and heavens knew how many other continents after it. Not for the first time, Lyon cursed his own naivety. Why had he not listened to Knoll? He should never have touched the Fire Emblem, much less split it. Had he known this would be the consequence of that simple act, he would never have done it.

 _Or would you?_ An otherworldly, bone-chilling voice said. Lyon didn't bother looking around for the source. He knew he would find no one, anyway; Fomortiis spoke to his mind, not his ears. _Destroying my prison was not as simple as you think, Fleshling. It required a complicated spell with a lot of power._ It chuckled. _You spent so much time preparing. Researching. The lovely Princess Eirika could have stood before you naked and begging, and you would not have let your mind wander from it._

"Th-that was..." Lyon faltered, the mental image conjured up by Fomortiis's words putting a deep scarlet flush on his cheek. "That was because you were manipulating me!" It was the only sensible explanation. Somehow, the Demon King must have already reached out to him from within its prison, steering his mind in the right -wrong- direction.

Fomortiis laughed, a loud, mad cackle this time. _That is funny, Fleshling. You know as well as I do that that thing was impenetrable for any of my power or consciousness. Believe me, I tried. But your obsession was enough on its own._ Lyon's stomach turned over and he wanted to vomit. Deep down inside, he knew his invader was right. He _had_ been obsessed with claiming the power of the Fire Emblem for himself. But only for the noblest of reasons! He had wished to heal his father's terminal illness –the one that had ended up claiming his life before he could finish his research, which had been the first blow to his fortitude-, to prevent or minimize the damage from the great quake he had foreseen –which came closer with every passing day, pressuring him and weakening him further-, to help the people of Grado... _Bringing her to your bed wouldn't have been so bad either._ Fomortiis quipped, causing Lyon to grip his head in shame. _You've seen how easy it is to manipulate someone with all this power._

"Stop- stop saying these things!" he screamed. He wanted nothing more than for Fomortiis to be quiet. Having him invade and settle in his mind as if it was its good right had been bad enough. Knowing that it used his body and his magic and had undoubtedly already attacked Eirika and Ephraim with it was one thing. But more than anything else, the Demon King's almost ceaseless taunting and humiliation were what ate at him. "Stop saying these things... about her..."

 _I'm going to see her, you know._ Lyon fell silent, quivering with his hand still between his hands. _At the river. What do you weaklings call it? Narube?_ Lyon knew what it meant. The river separated Renais, Jehanna, and Rausten from one another. That meant that with the Sacred Stone of Renais in hand, Eirika was headed for Rausten to get another one! With two Sacred Stones, surely they could- _Don't get excited. I'm not going to congratulate her on her luck. I wonder what would be more enjoyable; watching your magic rip her apart or simply drowning her in the waters._

"Don't you dare!" Lyon shouted, mortified. Narube River was a deep, quickly flowing river with an extremely powerful current. It was internationally agreed on that falling into it was as good as a death sentence for even very strong swimmers. If Fomortiis pushed Eirika into it... But he supposed it would still be a more pleasant death than his own magic, he thought. He had seen what Naglfar did to human bodies when he had experimented on corpses, and the tome itself described in very vivid detail how it mauled and tormented its victim's mind as well. "If you lay a finger on her, I'll-"

 _You'll what?_ Fomortiis said, and immediately afterward, Lyon lost consciousness and control again. When he returned, he would know that in the end, he was hopeless to resist it.

But he fought. The Demon King used his body as it pleased, issuing orders to its soldiers and instructing Riev (who Lyon swore sapped away some of his power every night so he would submit more easily) to go ahead to Darkling Woods and prepare the ritual, but had to stop periodically when Lyon woke up and tried to regain control of his body. "Stop that," it finally rumbled. "You won't save her." Yes, he would. He would save Eirika from being killed in one of at least two gruesome and painful ways.

When the Demon King reached towards his desk to grab a tome to bring, Lyon acted. Using all the mental strength he had, he delivered a blow to his own brain. Fomortiis cried out and brought up his left hand to clutch his temple, where the pain was located. Now that it had a body, it was easy to hurt and distract- something Lyon couldn't do when he was in control. But using the pain as a distraction, he took control of his neglected right arm and snatched up the tome next to Naglfar, immediately releasing control when he held it. It was possible to steal control back, then, but only if the Demon King was sufficiently mentally distracted. Fortunately, it had not noticed that the motion of his right hand had been of Lyon's will and not its own, and simply held the tome against his side as it cast a spell to teleport his body to the river.

If Lyon had had a body, he would have sighed in relief. Fenrir was no less physically pleasant a spell to be struck by than Naglfar, but it held a lot less power and was unable to alter or maim the target's mind. Ephraim would be proud of him.

The next time he found enough strength to regain consciousness, he realised Fomortiis had taken a blow from Eirika's blade. It was odd, to realise that and not feel the sharp pain followed by the burn as the sacred sword caused sparks to scorch the edges of the wound. Fomortiis roared in pain, however, its control wavering as the sensation it wasn't accustomed to distracted it, and before he could cast Fenrir to counter, Lyon reached out, grabbing hold of as much power as he could, and held it back so it could not be poured into the spell. It would be cast at half power at most, barely fast enough to graze Eirika when she ducked onto her horse's neck. He didn't need to see his own face to know Fomortiis was _livid._ "WHAT ARE YOU DOING!?" it roared, giving Eirika pause.

Still, Lyon would not be intimidated. He would not allow the Demon King to hurt Eirika. He reached out again, this time to muffle the defensive shield Fomortiis had erected around his body, allowing Eirika's rapier to connect with it fully and wound it much more gravely than before. "Stopping YOU!" Lyon screamed, realising he had wrestled back control. The pain was immense, and the shock in Eirika's eyes was too much to bear.

It was only for a split second though, as Fomortiis took control back by force and sent him hurtling back into an abyss of nothingness, where he would stay for hours this time.

He woke up in a bed, in a macabre fortress. They were in Darkling Woods, he realised, where the Demon King's power was stronger. Apparently, he had enraged Fomortiis with his brief instance of rebellion. _Was that it?_ He heard the Demon King mutter in the back of his head, more to itself than to Lyon. _Was her presence so powerful? Were you so desperate to protect her that you became strong enough to hinder me?!_ It was enraged, and Lyon winced. It had taken a leaf from his book and used its influence to hurt his head.

"I love her," he said through clenched teeth. He wished he could have said it to her instead, but here he was. "I will do everything in my power to keep you from hurting her. She is my strength."

 _Is that so? In that case, there's something you may want to see._ His legs stopped obeying and he walked over to a wall-height mirror, affixed to the wall opposite the door. _Think of her. Like you always do._ Lyon didn't want to obey, knowing he wouldn't like what he was about to see. What was it Fomortiis wanted? What was the mirror for? Was it going to show him Eirika's lovely form mangled beyond recognition? The life leaving her eyes as his spells struck her? But of course, the thought of those scenarios must have been enough, for his own image in the mirror started to distort, colours swirling in the glass. _Not what I had in mind, but it'll do,_ Fomortiis said. _Look closely. That's your precious Eirika as she is right now._

It was. She wore the same clothes she had during the battle, even though they were still stained with blood and heavily damaged, exposing part of her sides, arms, and calves. She must have been too busy tending to the wounded and planning the rest of the journey with the others, Lyon thought. He was so proud of her. He knew how she hated bloodshed and war, but she'd developed into a fine leader, even if she had the strategic geniuses of Ephraim and Prince Innes as well as the endless charisma and optimism of Princess L'Arachel at her side. There was no denying the effect she herself had on their soldiers. _Let's see how you feel about that after this._ Would this thing never let him have any thoughts to himself- wait, who was that?

Lyon wracked his brain to put a name to the face of the red-haired man who had walked up to Eirika and now spoke to her, concern evident on his sharp and handsome features. Seth. Of course. The general of Renais' military and Eirika and Ephraim's personal guard- he had often accompanied them to Grado during their visits and his prowess was well-known across the continent. Lyon hadn't immediately recognised with his face showing so much emotion towards his princess.

He couldn't hear what they said and he had never learnt lip reading, so he was dependent on their body language to understand their interaction. But that body language was clearer than crystal. Seth took Eirika's hand, concern not leaving his face even as Eirika smiled at him –did he have any idea how lucky he was to be on the receiving end of that smile?- and shook her head, undoubtedly reassuring him. Lyon's fist clenched involuntarily when he saw the knight put a hand on Eirika's exposed side. He knew it was probably to emphasize that she was injured, but there was something... intimate about it. Seth had never physically touched her anywhere else than her hand in the past. This was not a development he liked...

Eirika placed her hand over his and for a moment, Lyon hoped that she would push him away. But she didn't, only holding her hand there and continuing her conversation with him. She still smiled faintly, and slowly, the concern on Seth's face became washed away against something else. Lyon's stomach sank. He was not accustomed to seeing any emotion at all on the knight's face. Concern, anger, embarrassment; general Seth was well-known for his ability to keep his feelings completely under wraps. But the affection in his eyes as he touched his princess and held her hand was far too obvious, even if Lyon hadn't been completely lovestruck himself.

Fomortiis didn't have to taunt him when Eirika stepped forward, putting her arms around Seth's neck and embracing him tightly. Lyon took a step away from the mirror, putting his hands to his head as if to stem his sudden, skull-splitting headache. No. No! There was no- no, there was no mistaking it. The way Eirika embraced her knight was far too tight and put far too happy a smile on her face to be one of comfort and friendship. No, this was a lover's embrace, one he had so many nights dreamt of sharing with her himself.

 _That's it,_ the Demon King said. _See? She will never love you. All your effort to win her over was in vain._ Lyon screwed his eyes shut so he wouldn't have to look at it anymore, screaming his lungs out so he wouldn't have to hear Fomortiis anymore and falling to his knees as his strength left him.

He felt himself fading. Fomortiis was right. There was no point. He had always been weak. Too weak to fight temptation. Too weak to win Eirika over. So why would he have the strength to fight back again? He curled in on himself, both physically and mentally, as he felt the Demon King taking control of his body again and slowly getting to his feet. And yet, when Fomortiis spoke, he knew the sentiment that had formed the words was not only its own.

" _He will pay for this_."

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 _ **Additional Author's Notes:**_ _Please imagine this run of the game is done by someone very slow in support gathering so Seth and Eirika haven't had their A-support yet. Kthx._


End file.
